Detection of Recombinant African Swine Fever Virus Strains of p72 Genotypes I and II in Domestic Pigs, Vietnam, 2023

African swine fever virus (ASFV) genotype II is endemic to Vietnam. We detected recombinant ASFV genotypes I and II (rASFV I/II) strains in domestic pigs from 6 northern provinces in Vietnam. The introduction of rASFV I/II strains could complicate ongoing ASFV control measures in the region.

Potential for transmission of naturally mutated H10N1 avian influenza virus to mammalian hosts and causing severe pulmonary disease

Subtype H10 avian influenza viruses (AIV) are distributed worldwide in wild aquatic birds, and can infect humans and several other mammalian species. In the present study, we investigated the naturally mutated PB2 gene in A/aquatic bird/South Korea/SW1/2018 (A/SW1/18, H10N1), isolated from wild birds during the 2018-2019 winter season. This virus was originally found in South Korea, and is similar to isolates from mainland China and Mongolia. It had low pathogenicity, lacked a multi-basic cleavage site, and showed a binding preference for α2,3-linked sialic acids. However, it can infect mice, causing severe disease and lung pathology. SW1 was also transmitted by direct contact in ferrets, and replicated in the respiratory tract tissue, with no evidence of extrapulmonary spread. The pathogenicity and transmissibility of SW1 in mouse and ferret models were similar to those of the pandemic strain A/California/04/2009 (A/CA/04, H1N1). These factors suggest that subtype H10 AIVs have zoonotic potential and may transmit from human to human, thereby posing a potential threat to public health. Therefore, the study highlights the urgent need for closer monitoring of subtype H10 AIVs through continued surveillance of wild aquatic birds.

Severe acute respiratory syndrome coronavirus 2 and influenza A virus co-infection alters viral tropism and haematological composition in Syrian hamsters

The ongoing coronavirus disease 2019 pandemic and its overlap with the influenza season lead to concerns over severe disease caused by the influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infections. Using a Syrian hamster co-infection model with SARS-CoV-2 and the pandemic influenza virus A/California/04/2009 (H1N1), we found (a) more severe disease in co-infected animals, compared to those infected with influenza virus alone but not SARS-CoV-2 infection alone; (b) altered haematological changes in only co-infected animals and (c) altered influenza virus tropism in the respiratory tracts of co-infected animals. Overall, our study revealed that co-infection with SARS-CoV-2 and influenza virus is associated with altered disease severity and tissue tropism, as well as haematological changes, compared to infection with either virus alone.

Diagnostic performance and clinical feasibility of a novel one-step RT-qPCR assay for simultaneous detection of multiple severe acute respiratory syndrome coronaviruses

Coronavirus disease 2019 (COVID-19) is an acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Other coronaviruses (CoVs) can also infect humans, although the majority cause only mild respiratory symptoms. Because early diagnosis of SARS-CoV-2 is critical for preventing further transmission events and improving clinical outcomes, it is important to be able to distinguish SARS-CoV-2 from other SARS-related CoVs in respiratory samples. Therefore, we developed and evaluated a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay targeting the genes encoding the spike (S) and membrane (M) proteins to enable the rapid identification of SARS-CoV-2, including several new circulating variants and other emerging SARS-like CoVs. By analysis of in vitro-transcribed mRNA, we established multiplex RT-qPCR assays capable of detecting 5 × 10° copies/reaction. Using RNA extracted from cell culture supernatants, our multiple simultaneous SARS-CoV-2 assays had a limit of detection of 1 × 10° TCID₅₀/mL and showed no cross-reaction with human CoVs or other respiratory viruses. We also validated our method using human clinical samples from patients with COVID-19 and healthy individuals, including nasal swab and sputum samples. This novel one-step multiplex RT-qPCR assay can be used to improve the laboratory diagnosis of human-pathogenic CoVs, including SARS-CoV-2, and may be useful for the identification of other SARS-like CoVs of zoonotic origin.

Development of a Multiplex RT-qPCR for the Detection of Different Clades of Avian Influenza in Poultry

Since the initial detection of H5N1, a highly pathogenic avian influenza (HPAI) virus, in 1996 in China, numerous HPAI H5 lineages have been classified, and they continue to pose a threat to animal and human health. In this study, we developed a novel primer/probe set that can be employed to simultaneously detect pan-H5 HPAI and two clades, 2.3.2.1 and 2.3.4.4, of H5Nx viruses using reverse transcription quantitative polymerase chain reaction (RT-qPCR). The sensitivity and specificity of these primer sets and probes were confirmed with a number of different subtypes of influenza virus and the H5-HA gene plasmid DNA. In particular, the multiplex RT-qPCR assay was successfully applied to the simultaneous detection of H5 HPAI and different virus clades in clinical field samples from a poultry farm. Therefore, this multiplex assay and a novel detection primer set and probes will be useful for the laboratory diagnosis and epidemiological field studies of different circulating H5 HPAI virus clades in poultry and migratory wild birds.

The design and synthesis of purine inhibitors of CDK2. III

Cyclin-dependent kinases (CDKs) belong to a class of enzymes that control the ability of a cell to enter into and proceed through the cell division cycle. Using purine as a scaffold, we have synthesized a number of nanomolar inhibitors of CDK-2/cyclin E. In this report, the synthesis of a series of piperidine-substituted purine analogs will be presented, as well as some of their in vitro and in vivo biological effects.

Effects of pathway and neuronal aging on the specificity of motor axon regeneration

Youth is a strong predictor of functional recovery after peripheral nerve repair, while adulthood is commonly associated with poor outcome. Identification of the factors responsible for this difference could form the basis for strategies to improve regeneration in adults. Preferential reinnervation of motor pathways by motor axons (PMR) occurs strongly in young rats, but is often absent in older animals, and thus parallels the overall trend for superior results in young individuals. These experiments evaluate the individual contributions of peripheral nerve age and motoneuron age to the decline in regeneration specificity (PMR) which accompanies the aging process. The femoral nerves of young and old Lewis rats were removed as inverted "Y" grafts from the femoral trunk proximally to the terminal muscle and cutaneous branches distally. These grafts were transferred from (1) old to young, (2) young to old, (3) old to old, and (4) young to young bilaterally in 10 individuals per group. After 8 weeks of regeneration, reinnervation of cutaneous and muscle branches was assessed by dual labeling with HRP and Fluoro-Gold. Motor neuron regeneration was random in old to old (mean muscle branch (M) = 159, mean cutaneous branch (C) = 168), but PMR was seen when young pathways were used in old animals (M = 163, C = 116). PMR was vigorous when either type of graft was used in young animals (young graft, M = 218, C = 134; old graft, M = 204, C = 127). In this model, motoneuron age appears to be the primary determinant of specificity. However, the pathway also makes significant contributions, as shown by the ability of young pathways to generate specificity in old animals. Manipulation of graft Schwann cell behavior might therefore be an appropriate strategy to improve outcome in older individuals.

Hand and wrist injuries in young athletes

Successful treatments of musculoskeletal injuries in the pediatric population demand a thorough understanding of the basic anatomy and its biomechanics, and the physiology of growth and development of the immature skeleton. In addition, good treatment outcomes rely on the treating physician being an effective teacher to the young athlete and the patient's parents, coaches, and trainers. At the same time, the physician must be a good student in learning the nature of the patient's sports and each patient's athletic ability and aspirations. Most pediatric hand and wrist injuries can be treated nonoperatively with proper immobilization techniques and activity modification, but cases requiring surgical intervention must be recognized promptly to avoid long-term complications.

Atraumatic osteonecrosis of the adult elbow

Osteonecrosis is a disease that leads to joint destruction and often involves large joints, such as the hips, knees, and shoulders. Nontraumatic osteonecrosis of the adult elbow, to the best of the authors' knowledge, has not been reported. Nine adult patients with atraumatic osteonecrosis of 11 elbows were identified. The mean age at presentation was 36 years (range, 26-63 years); five patients were women and four were men. Six elbows involved the capitellum, three involved the lateral epicondyles, one involved the trochlea and radial head, and one involved medial and lateral epicondylar disease. All patients were receiving corticosteroid therapy, and no relationship between the duration or the amount of corticosteroid use and the severity of the osteonecrosis was found. Seven patients with radiographic Stage I and Stage II disease responded well to nonoperative treatments consisting of activity modification, analgesics, and a brief period of immobilization. Nonoperative treatment failed in two patients with Stage III disease, and they had core decompressions for pain relief. One patient with late Stage III disease in both elbows underwent bilateral total elbow arthroplasties. In contrast to the pediatric population, osteonecrosis of the adult elbow potentially can lead to end stage arthritis. If the osteonecrosis is diagnosed early, nonoperative treatment may be effective in relieving pain, although the long-term results of these treatments remain unknown.

Agent orange and the risk of gestational trophoblastic disease in Vietnam

There have been claims of an increased risk for gestational trophoblastic disease (i.e., hydatidiform mole and choriocarcinoma) in Vietnam since the period of Agent Orange sprayings. In 1990, we conducted a case-control study in Ho Chi Minh City to investigate risk factors for gestational trophoblastic disease in Vietnam. Eighty-seven married women, all of whom had a recent pathologic diagnosis of gestational trophoblastic disease, identified in the Obstetrical and Gynecological Hospital, were included in the study. Eighty-seven married women who were admitted mainly in the surgery departments of the same hospital were the controls, and they were matched to cases for age and area of residence. Odds ratios (ORs), adjusted for matching variables and other potential confounders, were estimated with unconditional logistic regression. A statistically significant trend in risk was observed with previous live births (p = .01). Cases were found to eat less meat per wk (OR = 0.4, 95% confidence interval [95% CI] = 0.2-0.9 for > or = five meat dishes) and to own fewer consumer goods than controls. An increase in risk was associated with the breeding of pigs (OR = 5.7, 95% CI = 1.2-27.6 for raising three or more pigs). A cumulative Agent Orange exposure index was constructed, using the patient's complete residence history. No significant difference was found between cases and controls for this index (OR = 0.7, 95% CI = 0.2-1.8 for high-exposure category), nor was such a difference noted for the agricultural use of pesticides.

A pilot study of amiodarone with infusional doxorubicin or vinblastine in refractory breast cancer

Increasing evidence suggests that P-glycoprotein (Pgp) expression can mediate drug resistance in refractory breast cancer. We studied 33 patients with refractory breast cancer enrolled in a pilot study of oral amiodarone as a Pgp antagonist given in combination with infusional doxorubicin or vinblastine. Whenever possible, tumors were biopsied and Pgp expression was assayed. Patients received either 60 mg/m2 doxorubicin over 96 h or 8.5 mg/m2 vinblastine over 120 h by continuous intravenous infusion. Beginning with the second cycle of chemotherapy, 600-800 mg amiodarone was given orally each day. Patients who experienced toxicity due to amiodarone but were responding to chemotherapy were placed on quinidine. Partial responses were observed in 9 of 33 patients on study and were sometimes observed after the first cycle of chemotherapy, before amiodarone was given, suggesting that some patients may have responded to treatment because of the infusional schedule. Toxicities were primarily the known side effects of the antineoplastic agents and of amiodarone. The major amiodarone toxicity was gastrointestinal, with nausea, vomiting, anorexia, or diarrhea being noted in 21 patients. Biopsy samples were obtained from 29 patients and in 21 cases, viable tumor tissue was present and the results were interpretable. Of the 21 samples, 9 had Pgp expression as determined by immunohistochemical staining; 12 were considered negative. The presence of Pgp expression was associated with an acceleration of the time to treatment failure. Whereas normal-tissue toxicities related to the combination of a Pgp antagonist with chemotherapy were not observed, amiodarone was associated with too many untoward effects to be utilized as a drug resistance-reversing agent.

Viral infections and chemical exposures as risk factors for hepatocellular carcinoma in Vietnam

A case-control study investigating risk factors for hepatocellular carcinoma (HCC) was conducted in Hanoi, in the north of Vietnam, between 1989 and 1992. Male cases of HCC (152) diagnosed in 2 hospitals were included. Hospital controls (241) admitted mainly to abdominal surgery departments were frequency-matched to cases for sex, age, hospital and place of residence (Hanoi, province). Odds ratios adjusted for matching variables and other potential confounders were estimated using unconditional logistic regression, or exact non-parametric statistical inference when numbers were small. Positivity for hepatitis B surface antigen (HBsAg) was the main risk factor for HCC in this sample. Five subjects (3 cases, 2 controls) had been infected by hepatitis C virus (HCV), and none of them were carriers of HBsAg, giving an OR of 38 associated with HCV infection among HBsAG-negative subjects. Alcohol drinking was associated with HCC and interacted with HBsAg positivity. Agricultural use of organophosphorous pesticides (30 liters/year or more) and military service in the south of Vietnam for 10 years or more were also associated with an increased risk of HCC. This study confirms the major role played by HBV infection and its association with HCC in south-east Asia. It also suggests how other factors such as alcohol consumption or exposure to chemicals may interact with HBV infection.

A new class of high affinity ligands for the neurokinin A NK2 receptor: psi (CH2NR) reduced peptide bond analogues of neurokinin A4-10

Analogues of [Leu10]NKA4-10 were synthesized in which each of the amide bonds was sequentially replaced with the reduced amide psi (CH2NH) bond to determine the effect of this structural modification on the antagonism of NKA binding to the HUB NK2 receptor. [psi (CH2-NH)9,Leu10]NKA4-10 (6) retained significant affinity for the NK2 receptor (IC50 = 115 nM) and showed weak partial stimulation of PI turnover (approximately 10-15% of NKA maximum). 6 behaves as a competitive antagonist of NKA-stimulated PI turnover with a pA2 = 6.7. The secondary amine of the psi (CH2NH) moiety of 6 was converted to a tertiary amine by alkylation. This modification was found to have a small effect upon receptor affinity but did result in attenuation of partial agonist activity. A combination of amino acid substitutions and psi (CH2NH) alkylation yielded [beta Ala8,psi (CH2N(CH2)2CH3)9,Phe10]NKA4-10 (21) which has very high affinity for the HUB NK2 receptor. This compound inhibited [125I]NKA binding with an IC50 = 1 nM which is equal to the receptor affinity of NKA. Compound 21 also shows very weak partial agonism of PI turnover (< or = 5% of NKA maximum) which makes this the most potent member of a new class of NKA ligands: psi(CH2NR)9-NKA4-10 analogues which potently antagonize NKA binding and possess minimal partial agonist activity.